there's an AU online car magazine
http://www.autospeed.com/index.html that tested this thing some time back and basically said it was snake oil. The most the device can do is help if the system has a large negative pressure region in the intake tract since it's really just a fan and not a sealed pressure system. The only way to know for sure would be to install a pressure gauge and see just what the value was at the MAF.
FYI, Most SVX owners have found little substantive gain from mods to the intake (pending some working on true superchargers/turbos)